1. Field of the Invention
The present invention relates to a sheet supplying apparatus that supplies a plurality of recording sheets, one by one, while separating the recording sheets from each other.
2. Discussion of Related Art
Generally, a conventional image recording device, such as a printer or a facsimile machine, includes an image recording portion and a sheet-supply cassette that accommodates a plurality of stacked recording sheets each as a recording medium, and supplies the recording sheets, one by one, from the sheet-supply cassette to the image recording portion so that the image recording portion may record an image on each recording sheet. For example, Patent Document 1 (i.e., Japanese Patent Application Publication No. 2004-149297 or its corresponding U.S. Patent Application Publication No. 2004-084831 A1) discloses a sheet supplying device including a sheet accommodating portion that accommodates a plurality of stacked recording sheets in their inclined postures; a sheet-supply roller that is pressed on the uppermost one of the stacked recording sheets; and a sheet separating portion that is supported by a bottom plate such that respective lower (i.e., leading) ends of the stacked recording sheets are held in contact with the sheet separating portion. The sheet separating portion includes a plurality of projecting portions that are arranged at regular intervals of distance, along a sheet-supply path along which each recording sheet is supplied; a plurality of pairs of arm portions each pair of which supports a corresponding one of the projecting portions, on either side of the one projecting portion; and a continuous base portion that continuously connects the arm portions to each other and thereby supports the arm portions. The sheet separating portion is held by a holder that is formed of a metallic plate and is fixed to the bottom plate, such that the projecting portions project by respective predetermined amounts through an elongate hole of the holder that is elongate along the sheet-supply path. When the sheet-supply roller, pressed on the uppermost one of the stacked recording sheets, is driven or rotated to convey the uppermost recording sheet, the leading end of the uppermost recording sheet pushes an appropriate one of the projecting portions, and consequently the one projecting portion is moved downward into the elongate hole of the holder because of elastic deformation of the corresponding arm portion. Since, however, the other recording sheets than the uppermost recording sheet are not moved because the respective leading ends thereof are engaged with the other projecting portions that remain projecting from the elongate hole, only the uppermost recording sheet is separated from the other recording sheets and is conveyed forward.
Meanwhile, recently, there is known an image recording device including a housing and a plurality of sheet-supply cassettes that accommodate different sorts of recording sheets, respectively, and that are insertable into, and removable from, the housing. For example, Patent Document 2 (i.e., Japanese Patent Application Publication No. 11-59925) discloses a sheet supplying device including a first box-like sheet-supply cassette and a second plate-like sheet-supply cassette that is detachably attached to a top portion of the first cassette and that accommodates a plurality of recording sheets whose size is smaller than that of the recording sheets accommodated by the first cassette. When the first sheet-supply cassette is used, the second sheet-supply cassette is detached from the first cassette, so that only the first cassette is inserted into the housing. On the other hand, when the second sheet-supply cassette is used, the second cassette is attached to the first sheet-supply cassette, so that the second cassette with the first cassette is inserted into the housing. In the state in which the second cassette with the first cassette is set in the housing, a sheet-supply roller is pressed on the uppermost one of the recording sheets accommodated by the second cassette, so as to supply the uppermost recording sheet to an image recording portion; and in the state in which only the first cassette is set in the housing, the sheet-supply roller is pressed on the uppermost one of the recording sheets accommodated by the first cassette, so as to supply the uppermost recording sheet to the image recording portion. The first sheet-supply cassette has, in an end wall thereof an outlet opening that is commonly used to supply the recording sheets from both the first and second sheet-supply cassettes.
However, the sheet supplying device disclosed by Patent Document 2 does not. employ a sheet separating portion as disclosed by Patent Document 1 in such a manner that the sheet separating portion is applied to the outlet opening of the first sheet-supply cassette and is commonly used to separate, from each other, the recording sheets supplied from each of the first and second sheet-supply cassettes Thus, the conventional sheet supplying device does not meet two requirements, i.e., the decreasing of size of the device as a whole and the increasing of accuracy of the supplying of recording sheets.